SILO v0.3.0 — bilingual onboarding

SILO now asks users to choose Simplified Chinese or English on first panel open and remembers the choice locally. The selected language controls both interface copy and generated Continue, Optimize, and Burn prompts. This release also adds complete English and Chinese README files and bilingual marketplace prompts.\n\nValidation: 49 tests, UI structure check, desktop smoke, MCP smoke, skill validation, and plugin validation.